Electrical connectors are conventionally utilized to couple one electronic assembly to another. One type of electrical connector is a heat seal connector, which is typically manufactured from a flexible material, such as mylar, having graphite interconnects disposed thereon. The heat seal connector is bonded to an electronic assembly, e.g., a printed circuit board, in a process wherein heat and pressure are applied thereto. In automated processes, interconnects of the heat seal connector are aligned with corresponding conductive pads formed on the printed circuit board utilizing optical alignment techniques. Thereafter, a conventional heat seal machine is employed to apply both heat and pressure to the interconnects, thereby bonding the interconnects to the pads of the printed circuit board.
The heat seal machine generally comprises a heating platen which is heated by a heating element and around which a parting agent, such as a thin silicone sheet, is disposed. When the heating platen is lowered by the heat seal machine, the silicone sheet contacts the interconnects to transfer heat thereto while preventing the heat seal connector from adhering to the heating platen. After each application, the silicone sheet is advanced across the heating platen such that an unused portion of the silicone sheet is positioned between the heating platen and the heat seal connector during the bonding process.
A drawback to the use of conventional heat seal connectors and conventional heat seal machines, however, is the fact that the silicone holding and advancing mechanisms of the heat seal machines are usually very bulky. Therefore, typical alignment methods, in which the heat seal connector and the printed circuit board are optically aligned, can sometimes yield inaccurate results because the silicone holding and advancing mechanisms coupled to the heating platen can interfere with the image recorded by an alignment device, such as a camera. In an attempt to overcome the possibility of inaccurate alignment, some conventional heat seal machines perform the alignment operation prior to positioning a fixture containing the heat seal connector and the printed circuit board beneath the heating platen. Although, in this manner, the alignment can be more accurately performed, the movement of the printed circuit board and the heat seal connector to a location beneath the heating platen after alignment can disturb the alignment of the two parts.
Furthermore, because the silicone holding and advancing mechanisms typically extend outward from the heating platen, the areas surrounding the conductive pads of a printed circuit board must often remain cleared of components to prevent interference with the holding and advancing mechanisms during the bonding process. This is very undesirable because consumer devices, such as pagers, are becoming smaller and more streamlined, and, as a result, the space available on printed circuit boards must be utilized more efficiently to accommodate a greater number of electrical and mechanical components, i.e., resistors, connectors, etc.
Thus, what is needed is a heat seal connection process that does not prevent component placement in areas of a printed circuit board surrounding the regions where the heating platen contacts the printed circuit board. Additionally, the heat seal connection process should provide for more accurate alignment of the heat seal connector with the printed circuit board.